html, body {
    margin: 0;
    padding: 0;
}
button {
    width: 110px;
    height: 40px;
    border-radius: 3px;
}
h2 {
    margin: 30px 0;
}
.main {
    width: 100%;
    min-height: 100vh;
    padding: 20px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.operation {
    margin-top: 10px;
    width: 400px;
    display: flex;
    justify-content: space-between;
}

@media screen and ( max-width: 500px ){
    .operation {
        width: 80vw;
        display: flex;
        flex-direction: column;
        align-items: center;
    }
}
.operation select{
    width: 100px;
    height: 40px;
    padding-left: 5px;
}
.operation button {
    font-size: 16px;
    letter-spacing: 1px;
    background: #2297c7;
    color: #fff;
    border: none;
}
.operation button:hover {
    background: #27a6c7;
}
.main .imgs {
    margin-top: 60px;
    border: 2px solid #4b4b4b;
    display: none;
    flex-wrap: wrap;
}
.main .imgs .item {
    width: 80px;
    height: 80px;
    box-sizing: border-box;
    font-size: 20px;
    line-height: 80px;
    text-align: center;
    color: #fff;
    border: 1px solid #eee;
    background: #fff;
}
.main .imgs .item img {
    width: 80px;
    height: 80px;
}
.suc {
    display: none;
    position: fixed;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    background: rgba(0, 0, 0, .6);
}
.suc .content {
    position: absolute;
    width: 300px;
    height: 150px;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    margin: auto;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    border-radius: 3px;
    box-sizing: border-box;
    background: #fff;
}
.suc .content p {
    font-size: medium;
}
.suc .content button {
    border: none;
    background: lightblue;
    color: #fff;
}
.suc .content button:hover {
    background: #a1c9d6;
}